John Edwards was once a titan in the Democratic Party, one who, just seven years ago, was considered a top contender for the White House, until he was caught in one of the most sensational sex scandals in American history.

The scandal, which involved an illicit affair with a 2008 presidential campaign aide, followed by a love child and an intense cover-up, would be Edwards' undoing. His career in professional politics would be over.

It started in 2006. Many thought Hillary Clinton was damaged goods and Barack Obama, then just a rising star in the U.S. Senate, was too green for the 2008 democratic presidential nomination. The young, charismatic Edwards, having already established himself on the national stage as then-Sen. John Kerry's vice presidential candidate for an unsuccessful 2004 bid for the White House, was rapidly looking like the next president of the United States.

At the time, Edwards' greatest political asset was his wife Elizabeth, a breast cancer survivor and a doting mother to the couple's four children.

Ahead of the 2008 election campaign, Edwards traveled the country to drum up support for a presidential run, when he met a feisty unknown actress and movie producer named Rielle Hunter. According to Hunter, their love affair began with a California hotel encounter.

Eventually, Hunter told ABC News, that she went to a hotel room with Edwards, and she said he persuaded her to sit with him on the hotel room bed. After sleeping together, Hunter said she didn't expect the affair with Edwards to continue.

But the man who would soon be a candidate for president decided to pursue Hunter, risking it all to be with her.

"We could not get enough of each other on the telephone," Hunter said. "If we were not together, we would be talking on the phone about four hours every night. We couldn't hang up."

Edwards hired Hunter to make a behind-the-scenes film of the campaign, a perfect cover for their secret affair to continue while they were on the road together. But nine months after Hunter joined the campaign, their illicit bliss was shattered when Elizabeth Edwards heard a cell phone ring. It turned out to be the secret cell phone John Edwards had been using only to talk to Hunter. Elizabeth called back the number.

"And I said, 'Hey, baby.' Click," Hunter told ABC News.

When Elizabeth Edwards confronted her husband, he told her that Hunter was just a one-night stand, but their affair continued, even when Elizabeth's breast cancer returned, this time, incurable. On March 22, 2007, Edwards stood next to his wife when they announced at a joint-press conference that her cancer was back and what it would mean for his presidential campaign.

"We're going to always look for the silver lining," Elizabeth Edwards told reporters at the time. "It's who we are as people and we will continue to do it."

But behind that public front of a family united in tragedy, Elizabeth suspected her husband was still having an affair.